I have some trouble when I want to add a database.
_dataBase = QSqlDatabase::addDatabase(\"QPSQL\");
After calling this method I have
Use depends.exe on qsqlpsql.dll and found that this dll need libpq.dll from PostgreSQL\9.3\libfolder. Add libpq.dll to Debug folder and it works:)
qsqlpsql.dll
libpq.dll
PostgreSQL\9.3\lib
Debug